I'm guessing .fixed is the section containing the program code and data
values, meaning you're linking your program to run completely in RAM.
In any case, your program is simply too big to fit in that controller's
RAM. That's all.

Basically i am linking for both SRAM and Flash.
For SRAM build:
I am getting '`.fixed' will not fit in region'issue.
For FLASH build:
error: no memory region specified for loadable section `.init'
I have SRAM size of 48Kb , i dont think this is causing the issue.

Did you mix code from different examples? Please create a minimal
example with makefile, linker-scripts(s), startup-code and just enough
C-code reproduce the issue. Pack everything into a zip-archive an attach
it to a message here.